Why is the warning light on my freezer (lec)up?

Have had my lec (not sure what model) freezer on for two weeks and for the past week there has been a red light up with a black triangle on it. What does this mean? Also everything else in the freezer was frozen except my bread which was still soft and was in the top part of the freezer. It is a stand up freezer with 6 drawers and I keep it in a cupboard in my hallway. It was previously stored in an outside shed, moved to a garage whilst still off then brought up to my flat and switched on while in the cupboard (I waited for a fortnight before I switched it on to let everything settle). It has not been moved since then.